The Trump administration on Tuesday released a proposal that would allow for the proliferation of less-comprehensive, cheaper health plans restricted under the Affordable Care Act, marking one of the most significant efforts by Republicans to roll back the Obama-era health law.

The proposed rule would loosen restrictions on short-term insurance policies, which are low-cost plans that have fewer benefits and limited consumer protections. Such plans can now only be carried for 90 days, and the new proposal would allow them to...